When this was added it completely changed the game. So many possibilities we're opened up for map making. Just look at the stuff possible in 1.8, like captive Minecraft or infinity dungeon!

These blocks are the most powerful. Seriously. They are as strong as bedrock and can do anything, like allow you to be able to kill the wither one hit with your fist. I have no idea why anyone thinks that though other blocks are stronger/better.

Who says diamond block when you spend 9 diamonds to get one block that some troll breaks with -=AN IRON=- pickaxe. When of course with the command block you just type '/clear @p', add a pressure plate above it, and then get another that says '/set gamemode 2 @p' right next to the other and BOOM! The troll can't break your diamond block.

The every thing blockThe only reason this is not first is because some people don't know what it is